1. Technical Field
The present invention relates to cleaning solutions for a photoresist which are useful for cleaning a semiconductor substrate in the last step of a development process when photoresist patterns are formed. More specifically, it relates to a cleaning solution for a photoresist comprising H2O as a primary component, a surfactant and an alcohol compound, and a method for forming patterns using the same.
2. Description of the Related Art
As semiconductor devices become smaller, the aspect ratio (thickness of photoresist, or height/linewidth of formed pattern) of a photoresist pattern increases. As a result, the pattern is collapsed during a cleaning process.
When the height of the formed photoresist pattern extends beyond a critical height, capillary forces exceed the elasticity of the photoresist, thereby resulting in collapse of the pattern during the cleaning process. In order to overcome this problem, the adhesive force between an underlying layer to be etched and the photoresist is enhanced by increasing inner elasticity of the photoresist or by decreasing the surface tension thereof.
Generally, a method of forming photoresist pattern on a semiconductor substrate comprises the steps of forming an underlying layer, to be etched on the semiconductor substrate, forming a photoresist film on a top portion of the underlying layer, exposing a portion of the underlying layer to light and developing the exposed substrate. In the case of a positive photoresist, the photoresist film of an exposed region is removed by a developing solution to form a desired photoresist pattern.
The last step of the above method is a cleaning process of removing the residual photoresist film by spraying distilled water from a top portion of a spin equipment while the semiconductor substrate is spinning. In such process, the pattern collapses due to high surface tension of the distilled water.